React 组件生命周期

class Hello extends React.Component {
 
  constructor(props) {
      super(props);
      this.state = {opacity: 1.0};
  }
 
  componentDidMount() {
    this.timer = setInterval(function () {
      var opacity = this.state.opacity;
      opacity -= .05;
      if (opacity < 0.1) {
        opacity = 1.0;
      }
      this.setState({
        opacity: opacity
      });
    }.bind(this), 100);
  }
 
  render () {
    return (
      <div style={{opacity: this.state.opacity}}>
        Hello {this.props.name}
      </div>
    );
  }
}
 
ReactDOM.render(
  <Hello name="world"/>,
  document.body
);

class Button extends React.Component {
  constructor(props) {
      super(props);
      this.state = {data: 0};
      this.setNewNumber = this.setNewNumber.bind(this);
  }
  
  setNewNumber() {
    this.setState({data: this.state.data + 1})
  }
  render() {
      return (
         <div>
            <button onClick = {this.setNewNumber}>INCREMENT</button>
            <Content myNumber = {this.state.data}></Content>
         </div>
      );
    }
}
 
 
class Content extends React.Component {
  componentWillMount() {
      console.log('Component WILL MOUNT!')
  }
  componentDidMount() {
       console.log('Component DID MOUNT!')
  }
  componentWillReceiveProps(newProps) {
        console.log('Component WILL RECEIVE PROPS!')
  }
  shouldComponentUpdate(newProps, newState) {
        return true;
  }
  componentWillUpdate(nextProps, nextState) {
        console.log('Component WILL UPDATE!');
  }
  componentDidUpdate(prevProps, prevState) {
        console.log('Component DID UPDATE!')
  }
  componentWillUnmount() {
         console.log('Component WILL UNMOUNT!')
  }
 
    render() {
      return (
        <div>
          <h3>{this.props.myNumber}</h3>
        </div>
      );
    }
}
ReactDOM.render(
   <div>
      <Button />
   </div>,
  document.getElementById('example')
);